Sink strainer assemblies are commonly used in household sinks to strain the waste water that flows from the sink into the associated drain pipe and to stop the flow of water from the sink into the drain pipe so that water can be retained in the sink for dishwashing or other purposes. Prior sink strainer assemblies have not been totally satisfactory from the standpoint of reliability of holding water in the sink, reliability of operation, and cost of manufacture and assembly.
It is an object of the present invention, therefore, to provide an improved sink strainer assembly which is provided with a snap lock for maintaining the strainer assembly in a position blocking the flow of waste water into the drain pipe.
The sink strainer assembly of this invention is adapted to be connected to the upper end of the drain pipe and comprises a body member of upright tubular shape having a lower portion positioned in fluid communication with the upper end of the drain pipe, and an upper portion of a larger diameter than the lower portion. The strainer basket is positioned in the larger upper portion.
An upright post secured to the basket and extending both upwardly and downwardly from the bottom wall of the basket carries a spring pressed ball near its lower end for locking a stopper on the under side of the bottom wall of the basket in a position preventing flow of water from the body member into the drain pipe. To ensure sealing of the stopper, it is made of a resilient material such as rubber and the body member is shaped so as to form a seat at the juncture of the larger upper portion of the body with the smaller lower portion of the body.
A grid mounted in the lower portion of the body below the seat has an axial opening through which the post extends and when the post is pushed downwardly so as to seat the stopper on the body member, the spring pressed ball passes through the opening in the grid and snaps into retaining engagement with the under side of the grid when the post is released. This maintains the stopper in sealing engagement with the body member.
The post can conveniently be made of an inexpensive plastic material which is readily shaped to accept the spring pressed ball and formed with a convenient handle projecting upwardly into the strainer basket. The post is subjected to principally compressive stresses which enables it to be manufactured of plastic which is of lower strength than metal.
The seat on the body member is curved and rounded to facilitate sealing engagement with the stopper which is also tapered to facilitate its sealing engagement with the seat.
All of the above features cooperate to provide an improved sink strainer assembly which can be economically manufactured and used over a prolonged service life.
Further objects, features and advantages of the invention will become apparent from a consideration of the following description when taken in connection with the appended claims and the accompanying drawing.